Yes there was a large net outflow of income
Yes wealthy people have been leaving Massachusetts and similar states for years
Yes that trend is relevant to any conversation about tax policy

But at the same time
The number of higher earners leaving actually went down year over year
Outflows predate the tax and are heavily tied to Florida and New Hampshire which offer obvious tax advantages regardless
Total lost income was higher in 2021 than in 2023
And most importantly the new tax is bringing in billions in revenue and those receipts are growing

Both stories exist at the same time
There is real competitive pressure between states on tax and business climate
And the Massachusetts millionaire tax is simultaneously generating a lot of money for programs that voters said they wanted to fund

You can argue that this is bad long term policy that it may hollow out the future tax base or hurt the states ability to attract entrepreneurs
You can also argue that the tradeoff is worth it if the revenue goes to productive uses like infrastructure and education that themselves help long run growth

Those are serious arguments
What is not serious is pretending that one IRS data point settles everything and then framing it as If you believe in this tax you are just ignoring math